悬挂式止水帷幕基坑降水开挖对临近高铁桥墩影响

当含水层深厚时,基坑工程中常采用悬挂式止水帷幕,此时止水帷幕深度对基坑降水开挖引起的周边地表和建筑物变形有着重要影响。为了研究不同止水帷幕深度条件下基坑降水开挖对临近高铁桥墩变形的影响,采用三维有限元软件,对苏州某地铁车站基坑降水开挖过程进行数值模拟。结果表明:随着止水帷幕深度增加,临近基坑的高架桥墩沉降量逐渐减小,当止水帷幕深度41、91 m时,距基坑42.5 m处的高铁高架桥墩沉降量分别为31.88、4.18 mm;在悬挂式止水帷幕条件下,止水帷幕深度大于91 m才能满足基坑降水对临近高铁桥墩的沉降控制要求(≤5 mm)。

Impact of foundation pit dewatering and excavation with suspended waterproof curtain on adjacent high-speed railway piers

In the case of a deep aquifer, a suspended waterproof curtain is typically used in foundation pit engineering. The depth of the waterproof curtain exerts a crucial impact on the deformation of surrounding surface and buildings owing to dewatering and excavation of foundation pit. To study the impact of the dewatering and excavation of foundation pit on the deformation of adjacent high-speed railway piers under different depths of the waterproof curtain, a three-dimension finite element software was used to numerically simulate the dewatering and excavation of a subway station foundation pit in Suzhou. Results show that with increasing depth of the waterproof curtain, the settlement of piers adjacent to the foundation pits gradually decreases. When the depths of the waterproof curtain are 41 and 91 m, the pier settlements of the high-speed railway are 31.88 and 4.18 mm, respectively. Moreover, the settlement of the pier meets the control requirements (≤5 mm) only if the depth of the waterproof curtain exceeds 91 m.